Speeding causes a large number of car accidents and also increases damage resulting from such accident. Accordingly, the market of vehicular automatic cruise control products has been gradually expanded. That is, products to which a cruise control method of maintaining a vehicle at a set speed and an adaptive cruise control method of maintaining a proper distance between vehicles are applied have been widely distributed.
With a generalized use of a navigation system, the market for the navigation system is also growing and thus, the spread of a system associated with the navigation is predicted to increase. The system extracts a shape of a driving road from a map, calculates a curvature indicating a curved level of the road based on the extracted shape of the road, and controls a speed based on the calculated curvature.
However, it is difficult to calculate a precise road curvature using a precision of a general map used for navigation or guide. To solve the above issue, research on highly precise map production and precise measurement has been conducted. However, large amounts of costs and time are required to achieve the actual commercialization thereof.